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	<h1>Go程序的切片重组reslice</h1>
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			By wiseai | 2022-07-29 | 2 minutes
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			<h1 id="74-切片重组-reslice">7.4 切片重组 (reslice)</h1>
<p>我们已经知道切片创建的时候通常比相关数组小，例如：</p>
<pre tabindex="0"><code>slice1 := make([]type, start_length, capacity)
</code></pre><p>其中 <code>start_length</code> 作为切片初始长度而 <code>capacity</code> 作为相关数组的长度。</p>
<p>这么做的好处是我们的切片在达到容量上限后可以扩容。改变切片长度的过程称之为切片重组 <strong>reslicing</strong>，做法如下：<code>slice1 = slice1[0:end]</code>，其中 <code>end</code> 是新的末尾索引（即长度）。</p>
<p>将切片扩展 1 位可以这么做：</p>
<pre tabindex="0"><code>sl = sl[0:len(sl)+1]
</code></pre><p>切片可以反复扩展直到占据整个相关数组。</p>
<p>示例 7.11 <a href="examples/chapter_7/reslicing.go">reslicing.go</a></p>
<pre tabindex="0"><code>package main
import &#34;fmt&#34;

func main() {
	slice1 := make([]int, 0, 10)
	// load the slice, cap(slice1) is 10:
	for i := 0; i &lt; cap(slice1); i++ {
		slice1 = slice1[0:i+1]
		slice1[i] = i
		fmt.Printf(&#34;The length of slice is %d\n&#34;, len(slice1))
	}

	// print the slice:
	for i := 0; i &lt; len(slice1); i++ {
		fmt.Printf(&#34;Slice at %d is %d\n&#34;, i, slice1[i])
	}
}
</code></pre><p>输出结果：</p>
<pre><code>The length of slice is 1
The length of slice is 2
The length of slice is 3
The length of slice is 4
The length of slice is 5
The length of slice is 6
The length of slice is 7
The length of slice is 8
The length of slice is 9
The length of slice is 10
Slice at 0 is 0
Slice at 1 is 1
Slice at 2 is 2
Slice at 3 is 3
Slice at 4 is 4
Slice at 5 is 5
Slice at 6 is 6
Slice at 7 is 7
Slice at 8 is 8
Slice at 9 is 9
</code></pre>
<p>另一个例子：</p>
<pre tabindex="0"><code>var ar = [10]int{0,1,2,3,4,5,6,7,8,9}
var a = ar[5:7] // reference to subarray {5,6} - len(a) is 2 and cap(a) is 5
</code></pre><p>将 <code>a</code> 重新分片：</p>
<pre tabindex="0"><code>a = a[0:4] // ref of subarray {5,6,7,8} - len(a) is now 4 but cap(a) is still 5
</code></pre><p><strong>问题 7.7</strong></p>
<ol>
<li>
<p>如果 <code>a</code> 是一个切片，那么 <code>a[n:n]</code> 的长度是多少？</p>
</li>
<li>
<p><code>a[n:n+1]</code> 的长度又是多少？</p>
</li>
</ol>

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